Al-Ilma' ila Marifat Usul ar-Riwayah wa Taqyidi as-Sama' - is an important work on the science of hadith by Qadi Iyad ibn Musa, rahmatullahi ta'ala 'alayhi, the author of Kitab ash-Shifa.' This is a rare treatise relating to the obligation of seeking hadith, its excellence, its etiquette, sincerity in doing so and other matters relating to it.

Also included is the sharh Deebaj al-Muhadhab which relates to the terminology, Mustallah of Hadith. In addition to this, there is a treatise clarifying the issue relating to the ascendance and descendance of the excellence of the people of hadith.

About Qadi Yadh :

He is Abu'l-Qadl Iyad ibn Musa ibn Iyad al-Yahsubi, Qadi of Ceuta during
the time of the Murabitun. He travelled to Andalus to study and in
Cordoba he learnt from such luminaries as Ibn Rushd, the grandfather of
the Qadi and philosopher of the same name. Iyad was already accepted in
scholarly circles when he was eighteen and was appointed qadi (judge) when he was 35 becoming first the qadi of Ceuta in 515 AH/ 1121 CE and later Granada in Spain in 531 AH/ 1136 CE. He was exemplary in his knowledge of the sciences of hadith from which ocean he drew his astonishing work ash-Shifa. He also wrote the Foundations of Islam on fiqh, and Tartib al-Madarik on the luminaries of the school of Madina. He opposed Ibn Tumart's claim to be the Mahdi and was exiled to Marrakech where he was martyred.